Abstract: A stamper holder capable molding of a substrate having a high-quality. The stamper holder is mounted in a mold of a mold assembly that molds a substrate for an information recording medium, together with a stamper having a molding surface for forming micro asperities in a surface of the substrate, in a state where the stamper is fitted in an insertion hole formed through a central portion of the stamper. The stamper holder is formed such that an outer periphery thereof is increased in diameter on a side toward the molding surface compared with a reverse side thereof to form a sloped surface, and part or all of an outer peripheral surface of the stamper holder opposed to an inner peripheral surface of the stamper defining the insertion hole has a shape complementary to the inner peripheral surface of the stamper.

Abstract: There is provided an intermediate for an optical recording medium, which can be uniformly coated with resin by the spin coating method without using a resin coating-assisting member, and allows formation of a central mounting hole without burrs. The intermediate comprises a hollow cylindrical protruding portion protruding from one surface on which functional layers are formed and a circular recess formed in a central portion of the other surface and having a diameter equal to that of the central mounting hole, and a temporary central hole formed to extend through a central portion of the recess and having a diameter smaller than that of the recess. The protruding portion has an outer diameter smaller than the diameter of the mounting hole and an inner diameter not smaller than the diameter of the temporary central hole, and has a central axis thereof substantially aligned with a center of the temporary central hole.

Abstract: There is provided a mold component which makes it possible to mold a substrate for an optical recording medium which enables a functional layer having a uniform thickness to be formed thereon without using a resin-coating assisting member. A stamper holder holds a stamper thereon, and has a generally hollow cylindrical shape. An insertion hole formed through a central portion of the stamper has a diameter which is larger than an outer diameter of a cavity-side end of the stamper holder at a higher temperature of the holder than a normal temperature, and is slightly smaller than the outer diameter at the normal temperature of the holder. The cavity-side end inserted into the insertion hole at the higher temperature of the stamper is grasped by a rim of the insertion hole which is reduced in diameter at the normal temperature of the stamper.

Abstract: An information recording medium preform is used to manufacture an information recording medium which has a center mounting hole formed in a central part thereof, has at least one type of functional layer formed on a first surface thereof, and for which at least one of recording and reproduction of information is possible. A second cavity that is formed as one of a circular recess and a ring shaped concave and composes part of the center mounting hole on the first surface side is formed in a central part of the first surface of the information recording medium preform. A first cavity that is formed as a recess and composes part of the center mounting hole on a second surface on another side of the information recording medium is also formed in a central part of the second surface of the information recording medium preform.

Abstract: A stamper holder capable molding of a substrate having a high-quality. The stamper holder is mounted in a mold of a mold assembly that molds a substrate for an information recording medium, together with a stamper having a molding surface for forming micro asperities in a surface of the substrate, in a state where the stamper is fitted in an insertion hole formed through a central portion of the stamper. The stamper holder is formed such that an outer periphery thereof is increased in diameter on a side toward the molding surface compared with a reverse side thereof to form a sloped surface, and part or all of an outer peripheral surface of the stamper holder opposed to an inner peripheral surface of the stamper defining the insertion hole has a shape complementary to the inner peripheral surface of the stamper.

Abstract: There is provided an intermediate for an optical recording medium, which can be uniformly coated with resin by the spin coating method without using a resin coating-assisting member, and allows formation of a central mounting hole without burrs. The intermediate comprises a hollow cylindrical protruding portion protruding from one surface on which functional layers are formed and a circular recess formed in a central portion of the other surface and having a diameter equal to that of the central mounting hole, and a temporary central hole formed to extend through a central portion of the recess and having a diameter smaller than that of the recess. The protruding portion has an outer diameter smaller than the diameter of the mounting hole and an inner diameter not smaller than the diameter of the temporary central hole, and has a central axis thereof substantially aligned with a center of the temporary central hole.

Abstract: There is provided a mold component which makes it possible to mold a substrate for an optical recording medium which enables a functional layer having a uniform thickness to be formed thereon without using a resin-coating assisting member. A stamper holder holds a stamper thereon, and has a generally hollow cylindrical shape. An insertion hole formed through a central portion of the stamper has a diameter which is larger than an outer diameter of a cavity-side end of the stamper holder at a higher temperature of the holder than a normal temperature, and is slightly smaller than the outer diameter at the normal temperature of the holder. The cavity-side end inserted into the insertion hole at the higher temperature of the stamper is grasped by a rim of the insertion hole which is reduced in diameter at the normal temperature of the stamper.